The invention relates to a vehicle having a first partial onboard power supply system and having a second partial onboard power supply system which is electrically connected with the first partial onboard power supply system at at least a first nodal point, the first partial onboard power supply system comprising a first group of electric consumers (loads) and the second partial onboard power supply system comprising a second group of electric consumers (loads).
The electric onboard power supply system of a vehicle is a complex system with several active and passive components. German Patent Document DE 10 2007 017 187 A1 , for example, describes art onboard power supply system having voltage-sensitive loads of a vehicle with an engine start-stop function. The voltage-sensitive load is supported by way of a direct-voltage controller and a blocking element.
German Patent Document DE 102 48 658 A1 describes the voltage-related support of high-performance consumers by the parallel connection of a supercap module. The supercap module supports voltage-sensitive consumers, particularly during a start of an internal-combustion engine.
It is an object of the invention provide an improved vehicle having a first partial onboard power supply system and a second partial onboard power supply system, which is electrically connected with the first partial onboard power supply system, at at least a first nodal point, The first partial onboard power supply system includes a first group of electric consumers, and the second partial onboard power supply system including a second group of electric consumers.
This and other objects are achieved by a vehicle, according to the invention, wherein the first partial onboard power supply system comprises a starter, an onboard power supply system connected parallel to the starter and a first switch between the first group of consumers and the electric onboard power supply accumulator, and the second partial onboard power supply system comprises a first direct-voltage controller, an electric support accumulator module, which is switched parallel to the second group of electric consumers at a second nodal point, an interface of the first direct-voltage controller being connected with the first nodal point and has an electric center tap, which is connected with the first nodal point by way of a second switch.
In this document, the term “center tap” means that the electric potential, which decreases over the entire support accumulator module, according to the principle of a voltage divider, can be partially tapped at the center tap, i.e. in the case of an electric potential lower than the potential decreasing on the whole. This means that the support accumulator module supports, i.e. supplies with electric energy and power, the second group of electric consumers, and that, when the second switch is closed, the support accumulator module, by way of the center tap, additionally supports the first group of electric consumers.
According to a particularly preferred embodiment of the invention, the support accumulator module electrically comprises a first partial accumulator and a second partial accumulator in series. The center tap is situated between the first partial accumulator and the second partial accumulator.
The two partial accumulators may be constructed as self-sufficient energy accumulators, which jointly form the support accumulator module, or may be components of an energy accumulator which forms the support accumulator module.
In a further embodiment of the invention, the vehicle has an internal-combustion-power-type unit that can be started by a starter, in which case the vehicle is constructed as: (i) an internal-combustion engine vehicle having a generator that is connected with the first nodal point or with the second nodal point, (ii) a plug-in hybrid vehicle or hybrid vehicle having a high-voltage onboard power supply system that, by way of a second direct-voltage controller, is connected with the first nodal point, or (iii) an electric vehicle having a range extender motor and having a high-voltage onboard power supply system that is connected by way of a second direct-voltage controller with the first nodal point.
In addition to the first partial onboard power supply system and the second partial onboard power supply system, the vehicle may also have a high-voltage onboard power supply system which is electrically connected with the two partial onboard power supply systems by way of a direct-voltage controller, if the vehicle also has an internal-combustion engine. The internal-combustion engine is not necessarily to be used as a traction engine but, as in the case of a battery-operated electric vehicle with a range-extending additional motor, can also be used as an auxiliary.
According to a further variant of the invention, the first partial onboard power supply system and the first partial accumulator have a nominal voltage of between 12 V and 14 V, and the second partial onboard power supply system has a nominal voltage of between 12 V and 60 V.
Accordingly, the second group of electric consumers has a higher nominal voltage than the first group of electric consumers. The nominal voltage of the support accumulator module corresponds to the nominal voltage of the second group of electric consumers, and the nominal voltage of the first partial accumulator corresponds to the nominal voltage of the first group of electric consumers.
It is advantageous for the support accumulator nodule to be constructed of supercapacitor cells, or for the support accumulator module to be constructed of lithium ion cells.
Supercapacitor cells as well as lithium ion cells have a high cyclization capacity and a high current load capacity, which seems to make then particularly suitable for use as support accumulator components.
According to a further embodiment of the invention, the vehicle can take up a driving operation during which the first switch is closed and the second switch is open, or the first switch is open and the second switch is closed; the vehicle can take up an additional-start operation, during which the first switch is open and the second switch is closed; and the vehicle can take up an equilibrating operation, during which the first switch is closed and the second switch is closed.
This means that, in a driving operation in which the first switch is closed and the second switch is open, the onboard power supply system supports the first group of electric consumers and the support accumulator module supports the second group of electric consumers. In this driving operation, the onboard power supply accumulator can be charged at the first nodal point if the electric potential is sufficiently high, and the support accumulator module can be charged at the second nodal point if the electric potential is sufficiently high.
If the first switch is open and the second switch is closed in the driving operation, the support accumulator module will support the second group of electric consumers and the first partial accumulator will support the first group of electric consumers.
In an additional-start operation, the starter is actuated, in which case the first switch is opened and the second switch is closed. During the start, a voltage drop occurs at the onboard power supply system accumulator, from which the first group of electric consumers is uncoupled. Instead, the first group of electric consumers is supported by the first partial accumulator. In this case, the latter is possibly significantly discharged or charged. After the start, the first switch is closed and the second switch also remains closed, which is called an equilibrating operation. In the equilibrating operation, the second partial accumulator is discharged by way of a potential drop at the second nodal point or by way of a potential rise at the second nodal point, until the first partial accumulator and the second partial accumulator have a comparable relative charging state. Subsequently, the second switch is opened, whereby the driving operation is established.
The invention is based on the considerations indicated in the following.
There are vehicles with an internal-combustion engine which have a conventional 12 V onboard energy (power) supply system for supplying electric energy. Plug-in hybrid vehicles and battery-electric vehicles have an electrified drive train with a conventional 12 V onboard energy supply system and a high-voltage power supply system, the high-voltage power supply system being assigned to the electric supply of the drive train and the 12 V onboard power supply system being assigned to the supply of the additional electric consumers in the vehicle.
The conventional 12 V onboard power supply system architecture is hardly capable of meeting the demands as a result of the integration of additional consumers into the onboard power supply system, particularly of high-performance consumers, such as electric steering systems, electric roll stabilization systems or additional-start systems of hybridized vehicles.
It is therefore suggested to carry out a skillful expansion of the onboard power supply system at a voltage of 48 V for high-performance consumers and to wire up this voltage level with the 12 V level, so that the demands of high-performance consumers and additional-start systems can be met simultaneously while the stability criteria of the onboard power supply branches are observed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.